What happened
During the takeoff roll, the aircraft initially exhibited a leftward deviation at low speed. The pilot successfully corrected this initial drift. However, as ground speed increased to approximately 60 knots, the aircraft veered left again. This second deviation was not corrected, causing the aircraft to leave the paved surface and strike objects or terrain, resulting in damage to the propellers.
The investigation
Post-accident examination revealed that the nose wheel steering system had failed to function correctly during the critical phase of takeoff. Investigation into the mechanical status indicated that the nose gear was not properly configured for normal operation. Specifically, the system required a pre-takeoff check to ensure the steering mechanism was set to castor mode, allowing free swiveling rather than active steering control.
Findings
The primary factor contributing to the accident was the failure to perform the necessary pre-takeoff checks. A service bulletin issued on January 20, 1982 (SA-226 No. 103), explicitly stated that limits must be placed on the use of nose wheel steering and that pilots must verify the system is in castor mode prior to takeoff. The pilot did not ensure this configuration was correct, leading to uncontrolled directional deviation at high speed.
Safety message
Pilots must strictly adhere to pre-takeoff checklists, particularly regarding nose wheel steering configuration. It is critical to verify that the system is in castor mode before initiating takeoff to prevent loss of directional control.